Lecture

Optical Aberrations: Spherical and Chromatic

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

PHYS-317: Optics I

L'optique est un vieux domaine qui touche à beaucoup de sujets modernes, des techniques expérimentales aux applications courantes. Ce premier cours traite plusieurs aspects de base de l'optique: propagation, dispersion, interférence, diffraction, polarisat ...

Description

This lecture covers optical aberrations, focusing on spherical aberration and chromatic aberration. Spherical aberration is discussed in terms of longitudinal and transverse spherical aberration, as well as its correction methods. The lecture also explains astigmatism and coma aberrations, and how to minimize them. Additionally, it delves into field curvature and the Petzval surface. Chromatic aberration is explored through the dispersion of light in different materials, leading to the explanation of the achromatic doublet for its correction.

Instructor

Benjamin Dwir

Academic title: Dr. Birth date: 24.10.1959 Nationality: Swiss At EPFL since: 1988

Official source

Ontological neighbourhood

Physics

Optics: Geometrical optics

Related concepts (32)

Optical aberration

In optics, aberration is a property of optical systems, such as lenses, that causes light to be spread out over some region of space rather than focused to a point. Aberrations cause the image formed by a lens to be blurred or distorted, with the nature of the distortion depending on the type of aberration. Aberration can be defined as a departure of the performance of an optical system from the predictions of paraxial optics.

Chromatic aberration

In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing.

Spherical aberration

In optics, spherical aberration (SA) is a type of aberration found in optical systems that have elements with spherical surfaces. Lenses and curved mirrors are prime examples, because this shape is easier to manufacture. Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems. The effect of spherical aberration was first identified by Ibn al-Haytham who discussed it in his work Kitāb al-Manāẓir.

Coma (optics)

In optics (especially telescopes), the coma (ˈkoʊmə), or comatic aberration, in an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a comet. Specifically, coma is defined as a variation in magnification over the entrance pupil. In refractive or diffractive optical systems, especially those imaging a wide spectral range, coma can be a function of wavelength, in which case it is a form of chromatic aberration.

Defocus aberration

In optics, defocus is the aberration in which an image is simply out of focus. This aberration is familiar to anyone who has used a camera, videocamera, microscope, telescope, or binoculars. Optically, defocus refers to a translation of the focus along the optical axis away from the detection surface. In general, defocus reduces the sharpness and contrast of the . What should be sharp, high-contrast edges in a scene become gradual transitions. Fine detail in the scene is blurred or even becomes invisible.

Related lectures (64)

Optical Aberrations: Understanding and Minimizing

Explores optical aberrations, including spherical aberration, astigmatism, and chromatic aberration, and discusses methods to minimize them.

Optical Aberrations: Spherical and Chromatic

Explores spherical aberration, astigmatism, coma, and chromatic aberration in lenses.

Microscopy Objectives: Correction and Aberrations

Covers the correction of major optical aberrations in microscopy and the design of commonly used objectives like achromats and apochromats.

Optical Aberrations: Understanding Spherical, Chromatic, Coma, Astigmatism, and More

Explores optical aberrations in microscopy, including spherical, chromatic, coma, astigmatism, and more, impacting image quality and correction methods.

Electron Microscopy Components